System and method for retrofitting a burner front and injecting a second fuel into a utility furnace

ABSTRACT

This disclosure may relate generally to systems, devices, and methods for a injecting a compound through a sootblower, burner or other utility furnace hardware, such that the compound can be delivered to targeted areas on the inside of a utility furnace. In one embodiment, the compound is a chemical for improving environmental controls. In another embodiment, the compound is a fuel. In that embodiment, compound can facilitate retrofitting a burner to a dual fired utility furnace. In another embodiment, the compound is a chemical for removing slag from the furnace.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority toInternational Application No. PCT/US2013/044296, filed Jun. 5, 2013, andentitled SYSTEM AND METHOD FOR RETROFITTING A BURNER FRONT AND INJECTINGA SECOND FUEL INTO A UTILITY FURNACE, which is a continuation-in-part ofand claims priority to U.S. application Ser. No. 13/492,479, filed Jun.8, 2012, and entitled SYSTEM AND METHOD FOR INJECTING COMPOUND INTOUTILITY FURNACE, which is a continuation-in-part of and claims priorityto International Application No. PCT/US2010/059886, filed Dec. 10, 2010,and entitled SYSTEM AND METHOD FOR INJECTING COMPOUND INTO UTILITYFURNACE, which designates the United States and is itself a PCTcontinuation-in-part of and claims priority to U.S. application Ser. No.12/636,446, filed Dec. 11, 2009, and entitled SYSTEM AND METHOD FORINJECTING COMPOUND INTO UTILITY FURNACE, all of which are incorporatedherein by reference in their entirety.

FIELD OF INVENTION

The subject of this disclosure may relate generally to systems, devices,and methods for facilitating the injection of various compounds,including liquid and gas fuels, into a utility furnace.

BACKGROUND OF THE INVENTION

Utility furnaces are used in various industries for a variety ofdifferent purposes. Common issues associated between these variousindustries include the handling of the byproducts created by thecombusted fuel. These byproducts can decrease the utility furnaceefficiency and pose other pollution problems

In one example, the pulverized coal, used in various types of boilers,burns in a combustion chamber. The hot gaseous combustion products thenfollow various paths, giving up their heat to steam, water andcombustion air before exhausting through a stack. The boiler isconstructed mainly of interconnected elements such as cylinders such asthe super heater tubes, water walls, various larger diameter headers,and large drums. Water and steam circulate in these elements, often bynatural convection, the steam finally collecting in the upper drum,where it is drawn off for use. Water/steam tubes typically almostcompletely cover the walls of the passage so that they efficientlytransfer heat to the water/steam. As the coal is burned, ash and/orother products of combustion build-up on the tubes.

Presently sootblowers are available to aid in the removal of thesebuild-ups. Soot-blowers are mechanical devices used for on-line cleaningof ash and slag deposits on a periodic basis. They direct a pressurizedfluid through nozzles into the soot or ash accumulated on the heattransfer surface of boilers to remove the deposits and maintain the heattransfer efficiency. The soot and dust generated in combustion getdeposited on outer tube surfaces. This adds to the fuel requirements tomaintain heat transfer into the water/steam heated by the utilityfurnace. Running with added fuel in turn increases deposition ofbyproducts of fuel burning and also increases the chances of the tubesfailure by overheating. This eventually results in shutting down of thefurnace for repairs. All this can be avoided by soot blowing. Regularsoot blowing saves fuel and boiler downtime. In other words steam atconstant parameters is available over a longer period of time. Numeroustypes of sootblowers exist including but not limited to wall sootblower,long retractable sootblower, rotating element sootblower, helicalsootblower, and Rake-type blower. Under optimal conditions this ash isremoved from the surface of the tubes by pressured fluid (typically air,saturated steam or super-heated steam) delivered from sootblowers.However under suboptimal conditions the ash melts due to reaching itsfusion temperature and results in the formation of slag. Sootblowers areless effective at removing the slag.

The major problem with the formation of slag is that it insulates theelements, thus requiring the furnace to burn at a hotter temperature tocreate the same increase in water temperature. Excessive ash deposits ona coal-fired boiler's heat transfer surfaces will reduce its efficiency,and in extreme cases a boiler can be shut down by ash-related problems.Slagging incidents are a heavy drag on the global utility industry dueto reduced power generation and equipment maintenance.

The changing electricity market and political pressures have pushed theuse of fuels other than coal. For example, use of gas, biofuel, cofiredfuel, etc. has become widespread. These factors have led to coal-firedplants being operated under unusual loads. This change in operation hasaltered the effects of boiler slagging. The cofiring of other fuels withcoal, especially biomass, represents a large challenge to utilityfurnace operation. The ash chemistry of these alternative fuels is oftenvery different to that of the coals and has given rise to seriousproblems. The tendency of coal for slagging depends on its composition.The complex interaction between a boiler's operating conditions and thefuel chemistry makes the prediction of slagging difficult. Furthermore,the increasing pressure on coal-fired power stations to reduce emissionshas led to the development of technologies for the abatement of specificpollutants that impact on ash slagging. The new generation of pulverizedcoal fired plant, designed for high efficiency through the use of highsteam temperatures and pressures, present further challenges withrespect to ash slagging and fouling.

Various methods of removing the slag other than with a sootblower are inuse. For example in some power plants, engineers fire shotguns into thefurnace to break the slag off of the pipes. Other methods require takingthe furnace off line to deal with the problem. Other methods include aspecialized system that is located to access flue gasses whereby thesystem uses a specialized pressure source (i.e., different from thatused by the facility for the operation of the sootblowers) to force afluid into a feed tube, which mixes the fluid with a chemical comingfrom atomizing nozzles. The fluid and chemical is then injected into theflue gas stream which may allow incidental contact with areas affectedby slagging. However, this method requires enormous amounts of chemicalto be dumped into the flue gas stream which is difficult if notimpossible to understand as the flow dynamics in the furnace areconstantly changing. For example, the buildup of slag between tubesredirects the flue gas away from those tubes preventing the slag fromreceiving the chemical. Furthermore, the specialized equipment and thespecial access for introducing the chemicals from a specialized systeminto the utility furnace substantially increases cost. Thus, thesetechniques are less than satisfactory.

In dealing with the byproducts released into the environment(pollution), various systems associated with the utility furnacesprocess the byproducts before their release. However, better methods ofchemical processing of these byproducts are constantly sought after. Newutility furnaces are almost certain to be required to operate underconditions that facilitate carbon capture and storage, for compliancewith climate change driven requirements. While such requirements arefrequently sought in relation to coal fired furnaces they could alsoapply to a variety of fuel types.

While the problems and limitations of utility furnaces are clear, thereare few solutions. The presence of certain compounds in the utilityfurnaces have been experimented with and resulted in improved abilitiesto deal with slag and pollution. While the specific compounds varyacross the board depending on the specific chemistry of the fuel andproblem to be addressed, one uniform problem exists, there is noadequate delivery mechanism to inject the compounds into targeted spotsin the furnace.

A solution to the problem of delivering various compounds to targetedlocations of a utility furnace is needed. As such a solution to thedelivery of compounds into a utility furnace is presented herein.

SUMMARY OF THE INVENTION

In an example embodiment, an apparatus comprises: a mixing chamberconfigured to receive a compound operable to improve at least one ofharmful emissions and slagging in a utility furnace. In this embodiment,the mixing chamber is further configured to mix the compound with afluid to be injected into the utility furnace, and the fluid isdelivered by a fluid supply which is in place at the utility furnace.

In an example embodiment, a method comprises: attaching a compound feedto a mixing chamber connected inline with a fluid supply; supplying thecompound to the mixing chamber; mixing the compound with a fluid; anddelivering the compound and the fluid to a utility furnace.

In an example embodiment, a system comprises: a fluid supply deliveringa fluid under pressure for use at a utility furnace; a compound capableof improving efficiency of the utility furnace; a mixing chamberoperable to combine the fluid under pressure with the compound, whereinthe mixing chamber is configured to be removably connected to the fluidsupply; and a mechanism connected to the fluid supply that directs thefluid under pressure into the utility furnace.

In an example embodiment, a method of retrofitting a utility furnace isprovided. In this method, the utility furnace has a burner front, theburner front fires the utility furnace with a first fuel type, and theburner front supplies combustion air associated with the combustion ofthe first fuel type, and the combustion air comprises at least one of:primary air, secondary air, and tertiary air. The method comprises:connecting a source of a second fuel type to the burner front, whereinthe connection is configured to introduce the second fuel type into thecombustion air; wherein the first fuel type is a different type of fuelfrom the second fuel type.

In an example embodiment, a method of injecting a compound into autility furnace comprises: injecting a compound into a preexisting fluidstream; wherein the preexisting fluid stream is a fluid stream carriedin an already existing conveyance device, wherein the already existingconveyance device was connected to the utility furnace, in such a manneras to inject the preexisting fluid stream into the utility furnace,prior to retrofitting the utility furnace to provide the ability toinject the compound into the fluid stream; injecting the preexistingfluid stream, containing the compound, into the utility furnace throughone of a burner front and a sootblower. In this example method, thecompound comprises one of: a solid, a liquid, and a gas.

In an example embodiment, a method of injecting a compound into autility furnace comprises: delivering a compound into the utilityfurnace by injecting the compound into a delivery mechanism conveying acombustion air, wherein the combustion air is one of primary air,secondary air, and tertiary air, wherein the compound comprises a fuelthat is not a primary fuel for firing the utility furnace.

In an example embodiment, a utility furnace comprises: a burner; adelivery mechanism, wherein the delivery mechanism is configured todeliver combustion air into the utility furnace, wherein the deliverymechanism is configured to deliver combustion air into the utilityfurnace in the vicinity of the burner, wherein the combustion aircomprises one of primary air, secondary air and tertiary air; a fuelsource provided to the burner, wherein the fuel source is a first fueltype and is the primary source of fuel to the utility furnace; and acompound source, connected to the delivery mechanism, wherein thecompound source is configured to supply the compound into the combustionair in the delivery mechanism.

In accordance with various aspects of the present invention an apparatuscomprises a mixing chamber configured to receive a compound forimproving environmental and/or efficiency conditions in a utilityfurnace, wherein the mixing chamber is further configured to mix thecompound with a fluid which is in a pressurized fluid system in placewith the utility furnace and configured to inject the fluid and compoundinto a utility furnace.

In another exemplary embodiment, a system comprises a fluid supplyconfigured to deliver a fluid; a valve connected to the fluid supplywherein the valve is operable to control the fluid from the fluidsupply; a feed tube configured to connect to the valve and transport thefluid; a delivery device configured to connect to the feed tube andconfigured to eject the fluid into a utility furnace; a compound capableof improving the efficiency of the utility furnace; a hopper configuredto hold a quantity of the compound; an delivery system connected to thehopper and operable to transfer compound from the hopper; and a mixingchamber operable to receive the compound from the delivery system andcombine the compound with the fluid supply wherein, the mixing chamberis configured to be removably connected to the valve.

In another exemplary embodiment, a system comprises a fluid supplyconfigured to deliver a fluid; a valve connected to the fluid supplywherein the valve is operable to control the fluid from the fluidsupply; a delivery system configured to connect to the fluid supply; acompound capable of improving the efficiency of the utility furnace; amixing chamber operable to receive the compound from the delivery systemand combine the compound with the fluid supply; the mixing chamberlocated in line with the fluid supply; the fluid supply delivering amixture of fluid and compound to the air blowers of a burner, the airblowers connected in line to the fluid supply configured to inject themixture into the furnace.

Furthermore, in an exemplary embodiment a method comprises attaching amixing chamber inline with a fluid supply; delivering a compound to themixing chamber mixing the compound with the fluid supply forming amixture; delivering the mixture to a utility furnace through amanufactured sootblower; covering areas of the furnace accessible bysootblowers; and impregnating the compound to affected slagging areasregardless of changing flue gas flow dynamics.

Furthermore, in an exemplary embodiment a method comprises attaching amixing chamber inline with a fluid supply; delivering a compound to themixing chamber mixing the compound with the fluid supply forming amixture; delivering the mixture to a utility furnace through a burner;covering areas of the furnace accessible by the furnace; andimpregnating the compound to affected slagging areas.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages will become betterunderstood with reference to the following description, claims andaccompanying drawings where:

FIG. 1 is an exemplary utility furnace depicting sootblower locations;

FIG. 2 a is an exemplary retractable sootblower and an example ofdistribution from the retractable sootblower;

FIG. 2 b is an exemplary wall mounted sootblower and an example ofdistribution from the wall mounted sootblower;

FIG. 2 c is an exemplary wall mounted sootblower and an example ofdistribution from the wall mounted sootblower;

FIG. 2 d is another exemplary wall mounted sootblower and an example ofdistribution from the wall mounted sootblower;

FIG. 2 e is an exemplary array of wall mounted sootblowers and anexample of distribution from the array of wall mounted sootblower;

FIG. 3 is an exemplary embodiment of a flow process of a system forinjecting compound into a utility furnace;

FIG. 4 a is a cross section of an exemplary embodiment of a nozzle usedto mix various compounds and pressurized fluid;

FIG. 4 b is a cross section of an exemplary embodiment of a mixingchamber used to mix various compounds and pressurized fluid;

FIG. 5 a is cross section of an exemplary embodiment of an apparatus formixing a compound with a pressurized fluid;

FIG. 5 b is cross section of an exemplary embodiment of an apparatus formixing a compound with a pressurized fluid;

FIG. 6 is an exemplary embodiment of distribution of a compound from awall mounted sootblower;

FIG. 7 is an exemplary embodiment of distribution of a compound from aretractable sootblower;

FIG. 8 a is an exemplary embodiment of a system delivering compound intoair to a burner;

FIG. 8 b is an exemplary embodiment of a burner receiving compoundthrough secondary air;

FIG. 9 is an exemplary embodiment of a method of the present invention;and

FIG. 10 is an exemplary embodiment of a burner front configured toreceive a second fuel source in the combustion air near the exit of theprimary fuel source from the burner.

DETAILED DESCRIPTION

In accordance with an exemplary embodiment of the present invention,systems, devices, and methods are provided, for among other things,facilitating the injection of various compounds into a utility furnace.The following descriptions are not intended as a limitation on the useor applicability of the invention, but instead, are provided merely toenable a full and complete description of exemplary embodiments.

In accordance with various exemplary embodiments of the presentinvention, a compound may be injected into a utility furnace by mixingwith a pressurized fluid going into the utility furnace. In variousexamples the compound may be merely injected under pressure into thepressurized fluid. In various embodiments the system may be configuredto pull the compound into the fluid. These examples may be combined aswell. As will be discussed herein the terms nozzles and/or mixingchambers may be used to describe the devices, locations and situationsin which compound and the pressurized fluid are mixed. While each termmay be discussed in various examples and embodiments it is noted thateither term may be used without excluding the other from application inthe examples and embodiments.

In accordance with an exemplary embodiment, with reference to FIG. 4 a,nozzle 400 a may have a first side 404 a, an inlet side to the fluid,and a second side 402 a, an exit side to the fluid. Nozzle 400 a may bevariously sized to accommodate the equipment that it mates to. In oneexemplary embodiment nozzle 400 a may be approximately 1-3 inches indiameter at the outlet to accommodate common feed tube sizes used withutility furnaces. However, nozzle 400 a can be sized to fit variouscomponents. In accordance with one embodiment, nozzle 400 a may have avarying cross-section between the first side and the second side. Invarious embodiments, the varying cross-section of the nozzle maycomprise a long radius 412 a. The long radius may have its largestopening in the nozzle on first side 404 a and the smallest diametercross-section on second side 402 a. In accordance with an exemplaryembodiment, nozzle 400 a comprises a varying cross section that causes ahigh pressure on first side 404 a relative to a low pressure on thesecond side 402 a.

The nozzle may also have a compound entrance 408. In an exemplaryembodiment, the compound may be brought into nozzle 400 a via compoundentrance 408. Nozzle 400 a may also have a compound exit (also referredto herein as chemical injection port). In an exemplary embodiment thecompound exits nozzle 400 a via compound exit 406 a. In accordance withan exemplary embodiment of the present invention, nozzle 400 a may beconfigured for mixing a compound with a pressurized fluid stream.

In accordance with various embodiments, nozzle 400 a may be merely amixing chamber. For example, nozzle 400 a may be configured for mixing acompound with a pressurized fluid stream. This mixing occurs in responseto the compound coming into contact with the fluid being carried withinthe fluid supply. FIG. 4 a is illustrative of this in that the cavityinto which the compound exits, at the compound exit 406 a, is the samecavity into which the pressurized fluid exits at the second side 402 a,and thus forms a mixing chamber. The radius/varying cross section 412 ais beneficial in creating a condition in the system that draws thecompound into the mixing chamber. As such, all nozzles may be mixingchambers but all mixing chambers may not be nozzles.

In accordance with various embodiments, a mixing chamber may be employedto mix a compound and a pressurized fluid stream. With reference to FIG.4 b, mixing chamber 400 b may have a first side 404 b, an inlet side tothe fluid, and a second side 402 b, an exit side to the fluid. Mixingchamber 400 b may be variously sized to accommodate the equipment thatit mates to. In one exemplary embodiment mixing chamber 400 b may beapproximately 1-3 inches in diameter at the outlet to accommodate commonfeed tube sizes used with utility furnaces. However, mixing chamber 400b may be sized to fit various components.

The mixing chamber may also have a compound entrance 408. In anexemplary embodiment, the compound may be brought into mixing chamber400 b via compound entrance 408. Mixing chamber 400 b may also have acompound exit 406 b (also referred to herein as chemical injectionport). In an exemplary embodiment the compound exits mixing chamber 400b via compound exit 406 b. In accordance with an exemplary embodiment ofthe present invention, mixing chamber 400 b may be configured for mixinga compound with a pressurized fluid stream.

In various embodiments, a mixing chamber may comprise a point where acompound supply line and a fluid supply line intersect. In one example amixing chamber may be a distinct separate part added to a fluid supplyline. For example, mixing chamber 400 b may be added in-line. In anotherexample, a fluid supply line may be tapped into directly with a secondline. Compound may be delivered under pressure through the second lineinto the fluid supply line. In this embodiment, the mixing chamber maybe the point or region of the system where the pressurized fluid and thecompound intersect. Any of variety of fluid supply lines on a utilityfurnace may be accessible for incorporating a mixing chamber, includingplant instrument air, service air, primary air into the furnace,secondary air into the furnace, and/or tertiary air into the furnace.The fluid may further comprise steam or various pressurized watersources.

In an example embodiment, the fluid medium used in the sootblowers isair, and the compound added is just water. The water, in this example,can flash to steam and has proven effective in sootblowing in thisfashion. Thus, the mixing chamber facilitates retrofitting a sootblowerto be able to meter an amount of water into the sootblower air stream.

In various embodiments of the present invention, the nozzle may furthercomprise a valve 410. One exemplary embodiment, valve 410 may be a ballvalve. In another exemplary embodiment, valve 410 may be a gate valve.Valve 410 may control the flow of the compound. In accordance withvarious embodiments of the present invention, the flow of the incomingcompound may be stopped and started by opening and closing valve 410. Inother exemplary embodiments, valve 410 may prevent the compound fromflowing away from nozzle 400 a and only allow the compound to flow intonozzle 400 a. For example, valve 410 may be a check valve.

In accordance with an exemplary embodiment of the present invention, anapparatus for mixing a compound with a pressurized fluid streamcomprises a mixing chamber, a valve, and a feed tube. In thisembodiment, referring to FIG. 5 a and/or FIG. 5 b, nozzle 500 a and/ormixing chamber 500 b may be positioned between valve 506 and feed tube504. The pressurized fluid can pass through nozzle/mixing chamber 500a/b coming from valve 506 and flowing into feed tube 504. Furthermore,nozzle/mixing chamber 500 a/b may be configured to receive the compoundat entrance 508 and mix the compound with the pressurized fluid stream.

In various exemplary embodiments nozzle/mixing chamber 500 a/b mayinclude features which allow for the connection of nozzle/mixing chamber500 a/b to valve 506 or to feed tube 504. Such features might includeany of a variety of fasteners known in the industry e.g., bolts, weld,pressure fittings, bracketed flanges, etc. In other various embodimentsnozzle/mixing chamber 500 a/b may be an integral or integrated part ofvalve 506 or feed tube 504. For example, nozzle/mixing chamber 500 a/band feed tube 504 may be manufactured as one piece. In an alternateexample valve 506 and nozzle/mixing chamber 500 a/b may be manufacturedas one piece. Likewise, all three elements may be manufactured as onepiece.

In one exemplary embodiment, valve 506 is a poppet valve. In otherembodiments valve 506 is any of a variety of valves include but notlimited to diaphragm valves, pressure regulator valves, check valves,etc. In various embodiments of the present invention valve 506 can beany of a variety of valves used in the art whereby the valve controlsthe flow of fluid. Furthermore, valve 506 may be configured to adjustthe pressure of the fluid passing through.

As discussed above, the apparatus may further comprise feed tube 504. Invarious embodiments of the present invention, feed tube 504 may beconfigured to attach directly to either valve 506 or nozzle/mixingchamber 500 a/b. In an exemplary embodiment feed tube 504 may beconfigured to be detached from valve 506 and attached to nozzle/mixingchamber 500 a or 500 b inserted between feed tube 504 and valve 506. Inthis manner, an existing device may be retrofitted to include thenozzle/mixing chamber 500 a/b. As discussed above the feed tube may alsobe integrated with nozzle/mixing chamber 500 a/b and/or valve 506. Invarious embodiments, feed tube 504 may be configured to withstand thepressure and corrosion caused by any material flowing through it. Invarious examples, fluid may flow through the feed tube at 300 SCFM to1000 SCFM. However, depending on the application smaller or larger ratesmay be used. The feed tube may be comprised of hardened steel that iscapable of withstanding the mixture of the high pressure fluid and alsothe compound introduced at nozzle/mixing chamber 500 a/b. Further, othervarious materials may be used depending on the intended use of thesystem. In some instances the feed tube may be a component alreadyinstalled in a facility incorporating the apparatus.

In one exemplary embodiment of the present invention, the compoundintroduced at nozzle/mixing chamber 500 a/b may be any of a variety ofsolids, liquids, or gases that may beneficially be injected into autility furnace. Furthermore, the compounds should be configured suchthat they are capable of being transported in line through a pressuresystem. In various examples the compound may be caused to move throughthe system via a positive pressure or a negative pressure.

In accordance with an exemplary embodiment, a compound in solid form maybe sufficiently granular that it can pass through various types oftubing. In one exemplary embodiment, the compound may be a solid agentor a dry compound, being a substantially dry, granular solid havinginsignificant levels of humidity or liquid. In various exemplaryembodiments, the compound is delivered as a slurry, liquid, or gas. Forexample, delivering the compound as a slurry, liquid, or gas may bebeneficial where pumping is incorporated. This may be especially truewhere there are high pressures to overcome at the nozzle. In anotherexample, delivering the compound as a solid may be beneficial when thecompound is delivered by transport air created by a vacuum. Variousexamples of compounds used in the system may include, but are notlimited to, magnesium hydroxide, potassium hydroxide, sodium hydroxide,aluminum hydroxide, hydrogen peroxide, magnesium, kaolin, mullite,trona, sodium bromide, potassium bromide, magnesium carbonate,magnesite, micronized limestone, urea-based solids delivered dry or wet,and/or ammonia. Any such compound that may be desirable for a variety ofchemically reactive, cleaning, processing or other beneficial purposesinside of a utility furnace may also be incorporated. Thus, in anexample embodiment, where the compound is for example ammonia orurea-based, the injection of the compound may facilitate selectivenon-catalytic reduction in the furnace or the backend flue gas.

In one exemplary embodiment of the present invention, the fluidcomprises pressurized air. In other various embodiments the fluid mightcomprise steam. Moreover, the fluid may comprise any compressed orpressurized fluid capable of being injected into the system.

In accordance with an exemplary embodiment of the present invention, theapparatus for mixing a compound with a pressurized fluid stream(comprising a nozzle, a valve, and a feed tube) may be used or adaptedto a utility furnace. In an exemplary embodiment, and with reference toFIG. 3, the apparatus may also be incorporated into a larger systemwherein the system comprises compound feed mechanism 300 which comprisescompound 302, compound storage 304, and mixing chamber 306, coupledinline with fluid delivery system 320 which comprises fluid supply 322,valve 324, feed tube 326 and delivery mechanism 328 either removably orpermanently coupled to utility furnace 330.

The fluid, as contemplated in an exemplary embodiment of the system, maycomprise any of a steam, air or other compressed gasses or fluidstypically released in a utility furnace. In accordance with an exemplaryembodiment the fluid supply may be an air compressor, steamrecirculation system, pump, pressure vessel etc. Furthermore, the fluidsupply may be any commercially available mechanism capable of creating,maintaining, or adjusting these pressures as contemplated herein. Thefluid supply may be positioned and/or coupled to valve 324 directly orby means of other connections and/or devices.

In accordance with an exemplary embodiment of the present invention,referring to FIG. 7, the delivery mechanism may be lance 718 and/orinjection nozzle 720. In another exemplary embodiment, the deliverymechanism comprises the injection nozzle associated with a wall blower.In various exemplary embodiments, the delivery mechanism may be anypermanent or temporary fixture on the utility furnace. In variousexemplary embodiments of the present invention, a delivery mechanism isany component capable of delivering the pressurized fluid and/or fluidmixed with compound into a utility furnace.

In one exemplary embodiment, lance 718 may be capable of being insertedpartially or fully into a utility furnace. The lance tube is what iscarried and rotated into the furnace by a gearbox/motor attached to thesootblower. The lance tube may surround the stationary feed tube and issealed by a gland. In another exemplary embodiment, injection nozzle 720is configured to deliver the fluid supply and/or the fluid supplycompound mixture to specific locations inside the utility furnace, suchas to a wall as depicted in FIG. 2 b or out into an open chamber asdepicted in FIGS. 2 a, 2 c, 2 d and 2 e. Thus, the compound can bedelivered to the exhaust gas, exhaust chamber, combustion chamber,pre-combustion (e.g., burner), water walls, pipes, superheat tubes, theback pass, or any other element in a utility furnace or its exhaust gasstream.

With reference to the compound, as discussed above, the compound may bereceived by the nozzle. This compound may be stored in any of a varietydevices connected to the nozzle. In accordance with an exemplaryembodiment, and with reference to FIG. 6, a compound storage device 614may comprise a hopper with an auger feeder connected either directly orindirectly to nozzle 602. In one example, the compound is stored in anon-pressurized hopper. In one example, the hopper may store a wetcompound. In another example, the hopper may store a dry compound. Inaccordance with various other exemplary embodiments, compound storagedevice 614 may comprise a storage container and pressure mechanism. Insuch an embodiment, the compound may be stored and delivered by thepressure mechanism which may include pressurized vessels, gravity feed,pumps (including any of a variety of direct lift, positive displacement,velocity, buoyancy, centrifugal and/or gravity pumps), conveyors or anycommonly known apparatus capable of delivering the compound to the inletof the nozzle. For example, the pressure mechanism may comprise positivedisplacement pump 618. Pump 618 may be located with storage device 614.Pump 618 may also be located along delivery line 610, providing pressureto nozzle and or mixing chamber 602. Pump 618 may delivery a wetcompound to nozzle and or mixing chamber 602.

Various quantities of this compound may be incorporated in the use andfunctionality of the system herein discussed. In one exemplaryembodiment, upwards of 1000 lbs of compound per cleaning cycle may beinjected into a utility furnace for the removal of soot. However, thequantities can vary depending on the size of the utility furnace andpurpose for which the compound is being injected.

While the compound can be delivered and/or received by the mixingchamber/nozzle in a variety of ways as discussed previously, themotivation of compound through the mixing chamber/nozzle can also occurin a variety of ways. In accordance with an exemplary embodiment of thepresent invention, a vacuum may be present on the second side of nozzle400 a which may create a force which may draw sufficient amounts ofcompound into the fluid stream to be delivered with the system. In oneexemplary embodiment, nozzle 400 a may cause 60 inches of vacuum (i.e.,a drop in pressure expressed in inches of water). In various otherembodiments the vacuum can be greater or less than 60 inches of waterdepending on the application. For example, there can be no vacuum atnozzle 400 a but instead nozzle 400 a may create a zone of static or lowpressure compared to the fluids in the sootblower. Variations on theprofile of the nozzle can be optimized to produce a sufficient vacuumand/or a maximum pressure drop. In other various embodiments, thecompound may be pressurized by a pump or the like and introduced intothe fluid stream under pressure. Such pressurization can occur in anyway typical of the art including, but not limited to the forces createdby the devices discussed above.

Referring again to FIG. 3, and in an exemplary embodiment, fluiddelivery mechanism 320 as discussed above can be configured to deliver apressurized fluid flow into utility furnace 330. In one exemplaryembodiment, the utility furnace is a coal fired induction draft powerplant furnace. Moreover, a utility furnace may be any of a commerciallyavailable or custom furnaces including but not limited to boilers, HVAC,cokers, pulp and paper furnaces, etc. In an exemplary embodiment thefurnace may be any of a variety of boilers fired by a variety of fossilfuels including, but not limited to, coal, petroleum, natural gas, etc.In other various embodiments of the present invention, a utility furnacemight include any of a variety of boilers fired by alternative fuels,such as, for example, bio fuels or a combination of bio fuels and fossilfuels. In various exemplary embodiments of the present invention,utility furnace 320 may comprise furnaces used in a variety ofindustries including metal refineries, (e.g., cokers), pulp and paper,energy production, waste disposal, heating, etc.

Referring to FIG. 1, sootblowers can be located in numerous locationsaround a furnace. Variations in numbers and locations depend on the sizeand type of furnaces. Each location may be specifically targeted toallow access to particular elements or locations inside of the furnace.In an exemplary embodiment, these strategically located sootblowers canbe used to deliver compound into the furnace. For example, wall mountedsootblowers may be located in the primary combustion area of thefurnace. Also, retractable long lance type sootblowers may be located inthe superheater or back pass portions of the furnace. In accordance withvarious other exemplary embodiments, a utility furnace may have varioustypes of sootblowers located near superheaters, reheaters, convectionsection of horizontal tubes, the economizer and/or air preheaters.Furthermore, in various embodiments, compound injection may be used viapressurized fluid stream at any sootblower location.

In an exemplary embodiment of the present invention, and with referenceto FIG. 6, a coal fired furnace system may comprise wall mountedsootblowers 616. Wall mounted sootblower 616 may, for example be aDiamond Power Model IR-3Z sootblower or a Clyde Bergemann Model RW5E.Furthermore, wall mounted sootblower 616 may comprise any deviceconfigured to deliver fluid to the interior walls of a utility furnace.

In an exemplary embodiment, wall mounted sootblower 616 may comprisefeed tube 604 and valve 606. In one exemplary embodiment nozzle 602 isinserted between feed tube 604 and valve 606. For example nozzle 602 maybe retrofitted into wall mounted sootblower 616. In another example,wall mounted sootblower 616 may be originally constructed with nozzle602 between feed tube 604 and valve 606. In various exemplaryembodiments, nozzle 602 may be a component of a compound feed mechanism600 which comprises valve 608, feed line 610, transport air valve 612and compound storage 614. Valve 608 may be coupled to feed line 610.Feed line 610 may be coupled to transport air valve 612. Transport airvalve 612 may be coupled to compound storage 614.

In an exemplary embodiment, nozzle 602 may receive the compound fromcompound storage 614 and mix the compound with fluid flowing throughwall mounted sootblower 616. Wall mounted sootblower 616 may carry thecompound to any of a variety of utility furnaces. Wall mountedsootblower 616 may also deliver the compound to wall 630 or any targetedarea of the furnace reachable by wall mounted sootblower 616.

In various other embodiments, transport air valve 612 may also includecomponents capable of attaching pressurized air to feed line 610. Forexample, transport air valve 612 may also include a flow regulator, anair pressure regulator, and/or a filter. These components may enabletransport air valve 612 to function as an air pressure source so that itis possible to add additional transport air to move larger heavierquantities of the compound.

In an exemplary embodiment of the present invention, and with referenceto FIG. 7, retractable sootblower 716 may comprise feed tube 704 andvalve 706. In one exemplary embodiment nozzle 702 is inserted betweenfeed tube 704 and valve 706. For example nozzle 702 may be retrofittedinto retractable sootblower 716. In another example, retractablesootblower 716 may be originally constructed with nozzle 702 betweenfeed tube 704 and valve 706. In various exemplary embodiments, nozzle702 may be a component of a compound feed mechanism 700 which comprisesvalve 708, feed line 710, transport air valve 712 and compound storage714. Valve 708 may be coupled to feed line 710. Feed line 710 may becoupled to transport air valve 712. Transport air valve 712 may becoupled to compound storage 714.

In an exemplary embodiment nozzle, 702 may receive the compound fromcompound storage 714 and mix the compound with fluid flowing throughretractable sootblower 716. In various examples, the sootblower may be aLong Retract Diamond Power Model IK-525 or a Long Retract ClydeBergemann Model US. Sootblower 716 may comprise any device configured todeliver fluid into the interior of any of a variety of utility furnaces.Specifically, lance 718 and injection nozzle 720 may extend into theinterior of a utility furnace. Retractable sootblower 716 may thendeliver the compound to, for example, the wall, superheat pipes, or anytargeted area of the furnace reachable by retractable sootblower 716.

In various exemplary embodiments of the present invention, the nozzlecan be placed in line with any commercially available or custom builtsootblower including but not limited to a wall sootblower, longretractable sootblower, rotating element sootblower, helical sootblower,and rake-type blower. The nozzle may be included as a constituent pieceof the valve, the feed tube, or a combination of either. Furthermore,the sootblowers may be installed on a furnace before adding the nozzleand compound feed. Alternatively a sootblower can be installed on afurnace after it has been retrofitted with a nozzle.

In accordance with various exemplary embodiments, an apparatus mixes acompound with a pressurized fluid to be delivered into a utilityfurnace. The mixture of the compound and the pressurized fluid may occurinside the body of the nozzle or may occur as the nozzle delivers thecompound and pressurized fluid to the feed tube. The nozzle functions tomix the compound with the pressurized fluid stream. This mixture ofpressurized fluid and compound is then delivered into a furnace, eitherby means of a custom apparatus or commercial apparatus. Any apparatusthat functionally delivers the fluid compound mixture to the furnace iscontemplated herein.

For convenience a number of pressures and relative pressures may bediscussed herein. For example, a first pressure may be the pressure atthe poppet valve. This pressure is what is being put through thesootblower in the absence of the present invention. This pressure mayalso vary greatly due to a number of factors such as plant systempressure, poppet valve setting, and/or sootblower type. A secondpressure may be the pressure at the chemical injection port. The secondpressure is a function of the pressure drop across the nozzle. A thirdpressure discussed may be the pressure required to push the compoundinto the fluid stream running through the sootblower. The third pressuremay be formed on or behind the compound in order to deliver it to thesootblower. The third pressure may be created by a pump. In instanceswhere there is a sufficient vacuum at the chemical injection port or thesecond pressure, there may not need to be a third pressure to delivercompound. The pressures discussed herein are relative to atmosphericpressures. In various examples, functionality of the system with variouscommercially manufactured sootblowers was tested as shown in table 1.

TABLE 1 Pressure Pressure at Displacement Sootblower at Poppet ChemicalPump Manufacturer Medium Valve Injection Port Pressure Copes VulcanSteam 390 PSI  38 PSI 60 PSI T-40 Clyde Bergmann Steam 230 PSI    5 PSI20 PSI US Blower Diamond Power Air 165 PSI −2.5 PSI 10 PSI IK-525 Blower

In various examples, such as the test performed on the Copes Vulcan T-40(see Table 1), the pressure of the fluid at the poppet valve in autility furnace may be maximized in an attempt to deal with extremeslagging. In some instances the fluid pressures at the poppet valves maybe operated at higher pressures than the utility furnace manufacturerecommended pressure settings. High poppet valve pressures may translateinto high chemical injection port pressures. In such instances, a pumpmay be used to increase the compound pressure in order to overcome thepressure at the chemical injection port. Furthermore, depending on thesituation and/or the type of mechanism used to overcome the chemicalinjection port pressures, the compound may be introduced as a wet slurryin order to ease introduction into the pressurized stream.

In other examples, such as the test performed on the Clyde Bergmann USBlower (see Table 1), lower fluid pressures at the poppet valvecorrespond to lower fluid pressures at the chemical injection port. Insuch instances, lower pressures from the pump may be used in order toovercome the pressure at the chemical injection port. Again, thecompound may be introduced as a wet slurry in order to ease introductioninto the pressurized stream.

In still other examples, such as the test performed on the Diamond PowerIK-525 Blower (see Table 1), the still lower pressures at the poppetvalve illustrate the vacuum that may be created at the nozzle allowingsubstantially easier introduction of the compound into the furnaceregardless whether it is slurried or in dry form.

While the pressures at the poppet valve of the various sootblowers inthe industry may vary greatly depending on the type and condition of thesootblowers or the conditions of the medium, utility furnace, or otherfactors, it should be noted that the systems, devices, and methodsdiscussed herein are beneficial in adapting the sootblowers to receiveand disperse various compounds in the utility furnace regardless of thecountless variations.

In accordance with various aspects of the invention, as discussed above,the delivery mechanism may be any permanent or temporary fixture on theutility furnace. In various exemplary embodiments of the presentinvention, a delivery mechanism is any component capable of deliveringthe pressurized fluid and/or mix of compound and fluid into a utilityfurnace.

As may be typical of a burner in a utility furnace, the burner can bevertical or horizontal, having air blowers located around the burner. Onthe outlet of the air blower are devices with movable flaps or vanesthat control the shape and pattern of the flame from the burner. Theseair blowers can be classified as primary secondary and tertiarydepending on when the air is introduced into the furnace. Primary air isthe first air introduced into the furnace. Primary air is the firstcombustion air added to fuel being carried into the burner. Secondaryair is used to supplement and finely tune the primary air. Compound maybe injected into the furnace by supplying compound via plant utility airto the burner front. Then by routing high temperature tubing (or similarmaterial) from the burner front, outside the furnace, to the internalcombustion air delivered by the air blower devices.

In accordance with various embodiments, as illustrated in FIGS. 8 a and8 b, the compound may be delivered into the utility furnace through theburner. For example, the compound may be delivered to the primary air ator near the burner and introduced into the furnace with the primary air.Primary air provides the initial ignition oxygen for mixture with thefuel and subsequent combustion. In another example, the compound may bedelivered to the secondary air at or near the burner and introduced intothe furnace with the secondary air. Secondary air is additionalcarefully controlled air flow that allows the higher hydrocarbons toburn (e.g., trim air). In another example, the compound may be deliveredwith tertiary air. Tertiary air insures delayed combustion purposely forNOx combustion (e.g., super trim air used on low NOx burners). Invarious examples, the compound may be delivered to the furnace interiorat the burners through any air transport or openings available.

In accordance with various embodiments, a mixing chamber 802 may belocated in the fluid supply 820. As may be typical of a utility furnace,the fluid supply 820, which may be instrument air and/or plant utilityair, may be routed to the burner front. The compound may be deliveredfrom the compound delivery device 814 through delivery tube 810 andvalve 812 to the mixing chamber 802. In the mixing chamber the compoundmay be mixed with the plant utility air under pressure. The mixture ofthe compound and the pressurized fluid may then travel through the fluidsupply 820 to the burner front 824. Fluid supply line 820 may have avalve 822 to shut off compound delivery and/or regulate supply air tothe burner. From the burner front 824, high temperature line 840 may berouted to the air blowers 830 in the burner. As the high temperatureline 840 between the burner front 824 and the air blowers 830 is likelynot present on a commercial burner, the high temperature line 840 mayneed to be routed in the field on the burner. In one example, hightemperature line 840 may deliver compound to the primary air. In oneexample, high temperature line 840 may deliver compound to the secondaryair. In one example, high temperature line 840 may deliver compound tothe tertiary air. In on example, high temperature line 840 may delivercompound to one or more of the primary, secondary, or tertiary air. Theair from the air blowers carrying the compound exits the burner into theutility furnace.

The compound when introduced into the utility furnace adds a benefitover the already available pressurized fluid. In one exemplaryembodiment, MgHO₂ is the compound. In this example, MgHO₂ may bedelivered by sootblowers to slag coated steam/water pipes to aid in theremoval of slag. In this example, the MgHO₂ is suited specifically tobreaking up a variety of slag accumulations caused by coal based fuelsburned inside of the utility furnace.

In another exemplary embodiment, magnesium is added into a utilityfurnace to aid in the encapsulation of harmful by products. In otherexemplary embodiments, magnesium, kaolin, mullite, and/or otherbeneficial agents or combinations of these agents can be introduced intothe utility furnace. These agents can be introduced into the utilityfurnace, superheats, back pass, preheats, exhaust stream, or otherlocation to aid in the encapsulation of SO₂.

In another exemplary embodiment, multiple compounds can be injected intothe sootblowers to deal with inclement conditions such as lowtemperature. Dry has its advantages in extreme cold temperatures in thesootblower in the furnace; dry injection is a good option for injectingin the ducts and the discharge of the air pre-heaters. However due todifficulties in delivering dry compound at higher pressures,poly-ethylene glycol (PEG) mixed with other chemicals discussed above,for example, MgHO₂, may be a good combination as an alternative to dryinjection in extreme low temperature conditions. In accordance with oneembodiment, the PEG can be effectively mixed with the compound at 55-60%solids by weight. Furthermore, the PEG is EPA compliant to inject in thefurnace. In various other embodiments, the mixture of PEG and compoundcan be effective for dusting when transporting coal. Thus thiscombination functions as a dust inhibitor and slag suppressor.

In accordance with an exemplary embodiment and with reference to FIG. 9,a method is provided for introducing a solid compound into a furnace.The method comprises retrofitting a sootblower with a nozzle, such asnozzle 400 a in FIG. 4 a (step 910). Attaching the nozzle to a compoundfeed and receiving a compound into the nozzle (step 920). Supplying afluid through a sootblower (step 930). Mixing the compound with thefluid (step 940). Transporting the compound and fluid through a feedtube into a utility furnace (step 950). Various exemplary embodimentsmay further comprise, reacting the compound in the utility furnace (step960). Furthermore, in one exemplary embodiment, the method includesremoving the nozzle (which was installed in step 910) from the system(step 970).

In accordance with an exemplary embodiment, a user may retrofit thenozzle by installing it on an operational sootblower in use on anyutility furnace (step 910). For example, the user may separate thepoppet valve and feed tube in a sootblower (step 912) and insert anozzle by removably connecting the nozzle between the valve and the feedtube (step 914). When separating the valve and the feed tube thefastening mechanism is removed. For example, in some commercially usedsootblowers this mechanism is a 600 pound flange with four ½ in NPTstuds. In accordance with various embodiments the user may need toreplace the studs that originally held the feed tube and the poppetvalve together. The new studs may need to be longer in order to make upthe new distance added by the nozzle. For example when placing a nozzleinline with some commercial feed tubes and valves, 2 inch longer studsmay be used. The user may reconnect the valve and the feed tube with thenozzle in between (step 916).

In accordance with and exemplary embodiment, the user may attach thenozzle to a compound feed mechanism (step 920). As discussed above thecompound feed mechanism may deliver compound to the nozzle in a numberof ways. In accordance with one embodiment of the present invention, thecompound is drawn into the nozzle by a vacuum created at the nozzle.This vacuum may create a transport air stream. The compound may beinserted into the transport air stream in a variety of ways includingbut not limited to physical force (e.g., an auger), pressure, gravity,or vacuum. However, it may be possible to overload the transport air byintroducing too much compound (i.e., extreme loading) or too heavy acompound. When extreme loading or moving very heavy solids occurs,additional transport may be needed. As such, in accordance with anotherembodiment, the transport air may be pressurized coming from thecompound feed. For example, the pressurized feed can come from plantinstrument air and connect at the transport air valve (612 of FIG. 6 or712 of FIG. 7) of the compound feed mechanism. Likewise, in someembodiments the nozzle may only create a static or lower pressurecondition. In which case the compound may be pumped to the nozzle inorder to provide sufficient pressure to overcome the pressure at thenozzle.

In accordance with an exemplary embodiment, fluid may be suppliedthrough a sootblower (step 930). In one example, the fluid supply may beinitiated by opening the poppet valve. In accordance with various otherexemplary embodiments, the fluid supply may be initiated according tothe individual operation of the sootblower or other fluid supply anddelivery device.

In accordance with one embodiment of the present invention, the compoundmay be mixed with the pressurized fluid (step 940). In one exemplaryembodiment the compound may be combined with fluid supply into a laminarflow. The compound may be control fed into the transport flow stream. Inone exemplary embodiment and with exemplary reference to FIG. 7, valve708 may be opened after the sootblower is started. In one exemplaryembodiment, transport air is pulled by a vacuum through the compoundfeed mechanism into the sootblower fluid stream. In another exemplaryembodiment, the compound is forced through the nozzle by a pump. Thepump may be a part of the compound feed mechanism. The compound may bedelivered to nozzle 702 in response to the injection nozzle 720 being inthe correct location in the interior of the utility furnace. Thedelivery of the compound may be triggered by activating thetransportation device which may be, for example, an auger feeder,transport air, or a pump. As discussed before, the fluid streampressures at the poppet valve can vary greatly. As such, the chemicalinjection port pressure (i.e., the fluid pressure after the nozzle) mayalso vary greatly. The variations may be adapted to by adjusting thepressure created by the pressure device in compound feed mechanism andcompound storage mechanism (for example, the pump, auger, and/ortransport air). The mixing or infusion may occur after fluid has beenrunning through the sootblower. Due to the nozzle creating a vacuum, thepeak impact pressure (i.e., the pressure designed into the sootblowersystem as measured at the injection nozzle 720 to allow it toeffectively move ash in a furnace) may drop. In an exemplary embodiment,this pressure drop is compensated for by readjustment of the poppetvalve. This compensation may thus prevent negative effects on thecooling flow of the lance tube and/or the peak impact pressure. Similar,measures may be taken for a mixing chamber. While the mixing chamber maynot cause the same pressure drop as the nozzle any pressure drop due tothe mixing chamber can be compensated for.

In accordance with one embodiment of the present invention, the mixtureof pressurized fluid and compound may then be advantageously supplied totargeted portions of a utility furnace (step 950). Such locations maynormally be accessible only by means of the sootblower. For example,referring to FIGS. 2 a, 2 c, 2 d, and 2 e, various elements away fromthe wall may be the target. Referring to FIG. 2 b, the wall may be thetarget. Furthermore sootblowers are located throughout substantially theentire utility furnace. As such, in various embodiments a user is ableto deliver the mixture to a utility furnace through all types ofmanufactured sootblowers. The use of any sootblower in the utilityfurnace allows for covering areas accessible by the sootblowers.Furthermore, the delivery of the compound by the sootblowers installedon the utility furnace is possible without relying on flue gas. As suchreliance on the changing flue gas flow dynamics is avoided. Ultimatelythe quantity of chemical delivered can also be minimized through thetargeted effort.

In accordance with one embodiment of the present invention, the mixturemay react with the targeted elements on the interior of the furnace(step 960). Introducing the compound into a utility furnace may improvethe efficiency of the furnace. This is done by impregnating the compoundto affected slagging areas and chemically altering the buildup ofpollution, slag, or other deleterious elements in furnace. In anexemplary embodiment, the device is configured to more easily remove theslag after first chemically reacting with the slag. In one example, thismay allow the furnace to function on less fuel while maintainingsubstantially similar operating parameters.

In accordance with one embodiment of the present invention, the nozzlesmay be removed from the sootblower when finished distributing thecompound into the furnace (step 970). This will restore the sootblowerto its original condition. Once removed the nozzle and compound feedmechanism may be stored for use on the same sootblower or they may bemoved to another sootblower. In accordance with another embodiment ofthe present invention, the nozzle and/or compound feed mechanism may beleft in place for future use.

It may be understood herein with regard to the various aspects,embodiments and examples of the present invention, that a compound, forproviding environmental benefits to emissions gases, reducing slagging,and/or improving the overall efficiency of a utility furnace, may beinjected into the utility furnace through preexisting fluid systems(e.g., compressed air systems) by mixing the compound with the fluid inthe fluid systems. The mixture may be injected into the utility furnacethrough one more of preexisting devices on the furnace includingburners, sootblowers, access panels, fuel delivery, etc.

As stated above, the compound may be any of a variety of solids,liquids, or gases that may beneficially be injected into a utilityfurnace. In accordance with an example embodiment, the compound maycomprise a fuel. In an example embodiment, the compound comprises a fuelthat is substantially different from the primary fuel used to fire theutility furnace. For example, if the primary fuel for firing a utilityfurnace is coal, the compound may comprise a fuel that is not coal. Forexample, the compound may comprise a combustible gas or a liquid fuel.In one example, a solid fuel is a different type of fuel from a liquidfuel or a gas fuel. In an example embodiment, the compound can comprisea fuel such as natural gas liquid (NGL), natural gas (NG), methane,propane, butane, gasoline, fuel oil, #6 Bunker C, petroleum, biofuels,liquefied coal, hydrocarbon fuels, and/or the like. In one example, ifthe primary fuel is coal, the compound may comprise NGL. In anotherexample, if the primary fuel is fuel oil, the compound may comprisemethane. In an example embodiment, liquefied natural gas (LNG) is puremethane in a liquid form, and NGL is primarily ethane and a combinationof heavier hydrocarbons in a liquid form. The LNG or NGL may be in aliquid form under pressure, but may vaporize when injected into thecombustion air.

Adding a compound, such as a second fuel, to the furnace via a retrofitto the burner front, can facilitate improvement of at least one ofharmful emissions and slagging in a utility furnace. Variousimprovements are related to the reduced quantity of coal being burned.Nevertheless, despite the reduction in coal firing the utility furnace,performance can be maintained with the addition of the second fuel.Thus, retrofit of a coal plant by adding a second fuel type to thecombustion, for example by adding NGL, facilitates a reduction inparticulate matter. The retrofit can facilitate reduced slagging andfouling. The method of reducing the coal supplied to the furnace isconfigured to reduce the fly ash produced, and thus reduce the amount ofslagging that may occur. The reduction of coal is also configured toreduce greenhouse gasses created in the utility furnace. For example,there can be a nearly linear reduction in NOx, SOx and ash compared tothe coal reduction. Thus, in an example embodiment, the retrofit burnersat the utility furnace can be operated to consume between 1%-35% lesscoal that at base load prior to the retrofit. This means that NOx, Sox,and ash can be reduced as much as 1%-35% as well. Similarly, as much as35% less reagents can be used in the furnace. For example, if 35% lesscoal is used, 35% less ammonia could be used in the furnace. Clearly, agreat environmental benefit can be achieved by reducing these greenhousegasses, particulates, and reagent use.

Moreover, the ability to flexibly vary the amount or proportion ofprimary fuel and secondary fuel is highly beneficial. In one exampleembodiment, once the retrofit is complete, the proportion of primary tosecondary fuel can be adjusted without making any structural changes tothe burner front. This is in stark contrast to prior art retrofits thatconvert a single fuel fired utility furnace to a co-fired furnace. Inthe past, such retrofits would remove burners from the burner front andreplace them with the second fuel burner. Not only are such retrofitsvery expensive and time consuming, they are somewhat permanentoperations. For example, in a prior art retrofit, the burner front maybe modified to remove coal inputs and replace them with a second fuelsuch as specifically designed fuel oil inputs. At that point, if for anyreason one does not want to use or loses a supply of the second fuel,the retrofit utility furnace is only able to continue operating atreduced capacity (if at all) with the single fuel. A similarly expensiveoverhaul would be needed to return the utility furnace to its formeroperating capacity.

In contrast, in accordance with an example embodiment, a utility furnacecan be retrofit inexpensively and with flexibility. The furnace retrofitis configured to facilitate flexible operation of the utility furnace ineither single or dual fire mode, and/or to vary the ratio of the primaryand secondary fuel. This flexibility can be achieved without a shutdown,overhaul, or physical rework of the burner front. In an exampleembodiment, the ratio or operating mode can be changed while the furnaceis operating. In another embodiment, the changes are simply made whenthe furnace is not operating. Thus, in an example embodiment, the changein ratio or operating mode is made by selecting the desired fuel sourcesupply rates. The retrofit can be done without replacing the burnerfront, and in such a manner that the original installation functionaloperation can be returned to without any renovations to the burnerfront. In other words, after adding the ability to add a second fuel tothe combustion air provided at the burner front, the utility furnace canbe flexibly operated 100% on coal, or in dual fuel mode without anystructural changes. It is noted that even a dual fired burner could beretro-fit, according to the principles described herein, to add a thirdfuel source.

In an example embodiment, the reduction BTU's caused by reducing theprimary fuel is offset by adding the second (new) fuel. In this exampleembodiment, the original BTU rating for the burner is not exceeded, butthe burner can be operated at, near, or below its designed BTU rating.In this way, the retrofit of the burner front may be configured to notsignificantly change the operation of the furnace or require collateralchanges to other systems.

As additional benefits, this flexibility facilitates the operators ofthe utility furnace to take advantage of changing commodity prices ofvarious fuels on a constant basis and over long periods of time, withoutany costs to make structural changes, or delay to implement the newoperation parameters. Similarly, this flexibility facilitates theoperators of the utility furnace to make adjustments to achieveenvironmental compliance standards/metrics/goals. Again, thisflexibility is very helpful in the event that a fuel source becomestemporarily unavailable. For example, if the secondary fuel is naturalgas and the natural gas pipeline is shut down for some reason, theutility furnace can adjust to quickly return to single fired mode at100% capacity until the natural gas pipeline is functional again. Again,the flexibility described herein may facilitate supply chain moderating,such as if a plant begins to have too much coal piled on site due to along over haul, the plant can adjust the proportions of the two fuels toadjust the rate of use of one of the two fuels to balance out on sitestorage of that fuel, as desired.

In one example embodiment, the compound may be indirectly added to thefluid supply that is injected into the furnace. For example, and withreference to FIG. 8, the compound may be mixed with instrument air orclean/dry air that in turn conveys the compound to the combustion air(similar for sootblowers). This is most likely to occur when thecompound is a solid. In another example embodiment, the compound isdirectly added to the fluid supply that is injected into the furnace.For example, the compound may be added directly to the combustion air(e.g., primary air, secondary air, and/or tertiary air). In this exampleembodiment, the space around the burner in the burner front can be themixing chamber in which the combustion air and compound are mixed. Forexample, a gas, such as NGL can be directly delivered to the burnerfront, and added to the combustion air at or near the burner front.

It is noted, that throughout this disclosure various references havebeen made to use of plant instrument air, service air, soot blowing air,steam, or pressurized water sources. To the extent these fluid sourcesare pre-existing, which they often are, they are also generallyinstalled with redundancy and reliability measures in place. Thus, in anexample embodiment, the fluid stream used to inject the compound is areliable, redundant, pre-existing fluid stream. This facilitates arelatively inexpensive but reliable function for the injected compoundcompared to use of separate and new sources of the fluid stream.

With reference now to FIG. 10, a burner front 1000 can comprise aprimary burner tube 1010 having a primary outlet 1011, a water-tubeburner opening 1030, various air dampers, and a second fuel pipe 1020.In an example embodiment, a second fuel can be conveyed to burner front1000 via second fuel pipe or supply pipe (the “source” of the secondfuel) 1020. The pipe 1020 may be configured to enter the burner frontand to deliver the second fuel in the second fuel pipe 1020 to a point1021 near the primary burner outlet. The outlet of the second fuel pipemay be located in contact with or close to the primary fuel burner. Inthe example of a coal plant, a primary fuel coal burner tube has anoutlet opening near the burner opening into the furnace. The coal burnertube is configured to blow coal powder into a furnace 1050. The secondfuel pipe, for example, may be oriented to similarly blow the secondfuel into the furnace through the same burner opening 1030 in the waterwalls. In an example embodiment, the outlet of the second fuel pipe 1020is behind or even with the outlet 1011 of the first fuel pipe 1010(relative to the water-tube burner opening 1030) so that the coalabrasives do not wear down the second fuel pipe.

In an example embodiment, the second fuel pipe outlet 1021 lies in thewindbox or combustion air box 1060. In an example embodiment, the outlet1021 of the second fuel pipe is located between the outer diameter ofthe coal pipe and the inner walls of the windbox. The windbox deliverscombustion air to the furnace. This combustion air comprises primary,secondary and tertiary air. This air both carries and surrounds the fuelinjected into the furnace. In an example embodiment, the windbox is themixing chamber. In one example embodiment, it is noted that theproximity of the mixing chamber (i.e., the windbox) to the furnace meansthat the compound (fuel) and the combustion air may be coming togetherjust as they enter the furnace or just before entering the furnace.Nevertheless, the combustion air conveys the compound (second fuel) intothe furnace along with the primary fuel (e.g., coal).

In an example embodiment, the second fuel is injected in the combustionair in the vicinity of the burner. Many different burner designs exist,so the routing of the compound injection line (the second fuel line) mayvary depending on the burner type being retro-fit. Nevertheless, theprinciple may be the same for each burner design. For example, with NG,LNG, or NGL, the fuel line may be field routed based on the burnerdesign. The fuel line, in an example embodiment, is routed through thecombustion air path. See, e.g., FIG. 10. For example, the fuel line maybe routed on the outside of the burner tube (e.g., the coal burnertube), and in the combustion air flowing past the burner tube. In anexample embodiment, the fuel line 1020 is a pipe ending in a nozzle ringnear the outlet 1011 of burner tube 1010 outside the burner tube. In anexample embodiment, the pipe and nozzle ring are insulated from the coalburner tube, and/or is configured to stand off from burner tube 1010.This may facilitate a reduction in radiant heat to the fuel tube. Thus,in an example embodiment, the nozzles (header ring) is in the combustionair path, and not in the coal path. For example, the pipe may enter theair box, and run along or near the burner pipe, stopping short of orequal with the burner pipe tip. In an example embodiment, the secondaryfuel pipe 1020 comprises high temperature tubing or a similar materialpipe. In an example embodiment, the pipe and header for the secondaryfuel source does not extend past the exit of the coal burner pipe so asto not be in the flow of the coal being blown into the furnace.

In accordance with an example embodiment, a method of retrofitting autility furnace, specifically retrofitting an existing burner on theutility furnace is provided. In this example embodiment, prior to theretrofit of the existing burner, the burner is configured to supply asingle, first (original) fuel to the utility furnace. The example methodcomprises retrofitting the existing burner to be capable of supplying asecond fuel to the utility furnace, wherein the second fuel is not thesame as the first (original) fuel used on that burner. After theretrofit of the existing burner, the retrofit burner can changeoperation between co-fired mode and single fired mode or vary theproportions of the two fuels without physical rework to the burner. Inthis example embodiment, the first fuel is a solid and the second fuelis a liquid or gas. In another example embodiment, the first fuel is agas and the second fuel is a liquid. In another example embodiment, thefirst fuel is a liquid and the second fuel is a gas. In another exampleembodiment, the second fuel type is one of: a liquid and a gas. Inanother example embodiment, the second fuel type is NGL. In anotherexample embodiment, the second fuel type is LNG. In another exampleembodiment, the first fuel is supplied to the furnace in a coal burnertube and the second fuel is supplied to the furnace through a secondtube located outside of and proximate to the coal burner tube, whereinboth the coal burner tube and the second tube are located in the burnerfront windbox.

In one example embodiment, second pipe 1020 may be field routed along ornear the coal burner tube. Near the end of the burner tube, the secondpipe may circle a portion of burner tube 1010 to form a header tube withnozzles for injecting the second fuel into the combustion air. In anexample embodiment, any suitable nozzle can be used, and the nozzle sizecan be determined based on flow rate of the gas or liquid. In an exampleembodiment, the nozzles are oriented to spray the second fuel in adirection perpendicular to the fuel pipe. In this manner, the secondfuel is mixed with the combustion air and carried into the furnace.Moreover, any suitable nozzle orientation can be used.

In an example embodiment, the second pipe may have one or more valves toisolate the second fuel from burner front 1000. For example, the secondfuel pipe may have Class IV shut off valves 1071, modulating controlvalves 1072, and or the like. In various example embodiments, the valvesmay be manual valves or automatically controlled valves, such as programlogic control valves or distributed control system valves. The valvesmay be configured to work with the burner management system or thecombustion management system.

It is noted that the second fuel pipe and delivery mechanism is verydifferent from a typical fuel oil lighter. Lighters typically cannot bemodulated—they are generally binary on/off devices. Lighters are alsotypically limited in size and BTU output because they are only used toget the furnace started or to facilitate a controlled stop. Lighterscannot generate, for example, 30% or more of the furnace BTU's.

In an example embodiment, the second fuel may be supplied via a pipefrom a source of that particular fuel. For example, the second pipe maybe an NGL supply line. In another example embodiment, the pipe may besupplied from an onsite storage tank. For example, a large compressednatural gas or LNG or NGL storage tank could provide the fuel source.The second fuel may be supplied, for example, under pressure. In variousembodiments, if the fuel is a liquid, it can be atomized beforeentrainment in an air stream. Any suitable atomizing nozzle/technologycan be used to atomize the liquid fuel.

As discussed above, the compound can comprise various substances,chemicals, fuels, and the like. In particular, the stoichiometry of thereaction when the compound is injected is very often temperaturedependent. In other words, injecting the compound at the wrongtemperature could result in a less than complete reaction or no reactionat all. An advantage of injecting the compound through the pre-existingsootblowers and/or burner front, is that there are a very large numberof points within the furnace and backend flue gases for selecting whereto make the injection. There is a significant diversity of temperaturesacross these various injection points. Thus, in an example embodiment,the pre-existing sootblower locations provide a selection of temperaturediverse locations for injection of the compound. For example, H₂O₂ mayadvantageously be injected through the duct blowers spanning theeconomizer.

In the following description and/or claims, the terms coupled and/orconnected, along with their derivatives, may be used. In particularembodiments, connected may be used to indicate that two or more elementsare in direct physical contact with each other. Coupled may mean thattwo or more elements are in direct physical contact. However, coupledmay also mean that two or more elements may not be in direct contactwith each other, but yet may still cooperate and/or interact with eachother. Furthermore, couple may mean that two objects are incommunication with each other, and/or communicate with each other, suchas two pieces of hardware. Furthermore, the term “and/or” may mean“and”, it may mean “or”, it may mean “exclusive-or”, it may mean “one”,it may mean “some, but not all”, it may mean “neither”, and/or it maymean “both”, although the scope of claimed subject matter is not limitedin this respect.

It should be appreciated that the particular implementations shown anddescribed herein are illustrative of various embodiments including itsbest mode, and are not intended to limit the scope of the presentdisclosure in any way. Furthermore, the connecting lines shown in thevarious figures contained herein are intended to represent exemplaryfunctional relationships and/or physical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical system.

While the principles of the disclosure have been shown in embodiments,many modifications of structure, arrangements, proportions, theelements, materials and components, used in practice, which areparticularly adapted for a specific environment and operatingrequirements, can be made without departing from the principles andscope of this disclosure. These and other changes or modifications areintended to be included within the scope of the present disclosure andmay be expressed in the following claims.

Statements of Example Embodiments:

In an example first embodiment, an apparatus comprises: a mixing chamberconfigured to receive a compound operable to improve at least one ofharmful emissions and slagging in a utility furnace, wherein the mixingchamber is further configured to mix the compound with a fluid to beinjected into the utility furnace, and wherein the fluid is delivered bya fluid supply which is in place at the utility furnace. In this exampleembodiment, the mixing chamber receives the compound from a compoundfeed mechanism. In this example embodiment, the mixing chamber isconfigured to be retrofitted between a valve and a feed tube. In thisexample embodiment, the valve and the feed tube are located on asootblower. In this example embodiment, the mixing chamber is anintegrated component of a sootblower.

In an example second embodiment, a method comprises: attaching acompound feed to a mixing chamber connected inline with a fluid supply;supplying the compound to the mixing chamber; mixing the compound with afluid; and delivering the compound and the fluid to a utility furnace.In this example embodiment, the compound is supplied from a hopper tothe mixing chamber by at least one of a vacuum and a pump. In thisexample embodiment, the fluid is delivered to a sootblower. In thisexample embodiment, the method further comprises: retrofitting thesootblower with the mixing chamber, wherein retrofitting comprises:separating a feed tube and a valve on the sootblower; inserting themixing chamber between the feed tube and the valve; and connecting themixing chamber, the feed tube, and the valve together. In this exampleembodiment, the mixing chamber is located near a burner and the compoundis delivered to the utility furnace via a burner front of the utilityfurnace. In this example embodiment, the fluid supply is one of: plantinstrument air, service air, sootblowing air, steam, and pressurizedwater sources. In this example embodiment, the plant instrument air isconnected into the secondary air of the burner on the utility furnaceand the compound is delivered from the mixing chamber, via the plantinstrument air, into the secondary air and out of the burner front intothe utility furnace. In this example embodiment, the compound isMagnesium Hydroxide. In this example embodiment, the fluid is combustionair that comprises one of: primary air, secondary air, and tertiary air.In this example embodiment, the compound is a fuel. In this exampleembodiment, the fluid is combustion air that comprises one of: primaryair, secondary air, and tertiary air, and wherein the compound is a fuelcomprising natural gas liquid (NGL). In these example embodiments, thecompound is a gas or a liquid.

In a third example embodiment, a system comprises: a fluid supplydelivering a fluid under pressure for use at a utility furnace; acompound capable of improving efficiency of the utility furnace; amixing chamber operable to combine the fluid under pressure with thecompound wherein, the mixing chamber is configured to be removablyconnected to the fluid supply; and a mechanism connected to the fluidsupply that directs the fluid under pressure into the utility furnace.In this example embodiment, the system further comprises: a hopperconfigured to hold a quantity of the compound, wherein the mixingchamber is configured to receive the compound from the hopper; and apump system configured to deliver the compound from the hopper to themixing chamber at a pressure sufficient to overcome the pressure of thefluid under pressure. In this example embodiment, the compound isMagnesium Hydroxide. In this example embodiment, the mechanism is asootblower having a valve, a feed tube, and a delivery device connectedto the fluid supply, wherein the mixing chamber is connected inlinebetween the valve and the feed tube. In this example embodiment, thecompound, hopper, pump system, and mixing chamber are integrated with atleast one of a retractable or a wall mounted sootblower installed on theutility furnace. In this example embodiment, the mechanism is a burnerfront in the utility and the fluid supply is a plant instrument airrouted into a secondary air in the burner front, wherein the mixingchamber is on the plant instrument air, wherein the compound isdelivered from the hopper to the mixing chamber and mixed with the fluidunder pressure in the plant instrument air and then routed to thesecondary air in the burner front and out of the burner front and intothe utility furnace. In this example embodiment, the system isadjustable to operate the fluid supply at the same peak impact pressurewith the mixing chamber as compared to without the mixing chamber. Inthis example embodiment, the compound is added directly to the fluid inthe mixing chamber. In this example embodiment, the compound is atomizedat about the same time it is injected into the fluid.

In a fourth example embodiment, a method of retrofitting a utilityfurnace, wherein the utility furnace has a burner front, wherein theburner front fires the utility furnace with a first fuel type, andwherein the burner front supplies combustion air associated with thecombustion of the first fuel type, wherein the combustion air comprisesat least one of: primary air, secondary air, and tertiary air, themethod comprises: connecting a source of a second fuel type to theburner front, wherein the connection is configured to introduce thesecond fuel type into the combustion air; wherein the first fuel type isa different type of fuel from the second fuel type. In this exampleembodiment, the utility furnace is a coal fired furnace and the firstfuel type is coal. In this example embodiment, the second fuel type isone of: a liquid and a gas. In this example embodiment, the second fueltype is natural gas liquid (NGL). In this example embodiment, the secondfuel type is liquefied natural gas (LNG). In this example embodiment,the second fuel type is introduced directly into the combustion air. Inthis example embodiment, the second fuel type is introduced indirectlyinto the combustion air.

In a fifth example embodiment, a method of injecting a compound into autility furnace comprises: injecting a compound into a preexisting fluidstream; wherein the preexisting fluid stream is a fluid stream carriedin an already existing conveyance device, wherein the already existingconveyance device was connected to the utility furnace, in such a manneras to inject the preexisting fluid stream into the utility furnace,prior to retrofitting the utility furnace to provide the ability toinject the compound into the fluid stream; injecting the preexistingfluid stream, containing the compound, into the utility furnace throughone of a burner front and a sootblower; and wherein the compoundcomprises one of: a solid, a liquid, and a gas. In this exampleembodiment, the preexisting fluid stream is one of primary, secondary,and tertiary air. In this example embodiment, the compound is one of: aliquid and a gas. In this example embodiment, the compound is a fuelother than a primary fuel for firing the utility furnace. In thisexample embodiment, the preexisting fluid stream and the compound areinjected into the utility furnace through the burner front. In thisexample embodiment, the primary fuel is coal and wherein the compoundcomprises natural gas liquid (NGL).

In a sixth example embodiment, a method of injecting a compound into autility furnace comprises: delivering a compound into the utilityfurnace by injecting the compound into a delivery mechanism conveying acombustion air, wherein the combustion air is one of primary air,secondary air, and tertiary air, wherein the compound comprises a fuelthat is not a primary fuel for firing the utility furnace. In thisexample embodiment, the delivery mechanism is a burner front for theutility furnace, wherein the burner front comprises the burner andwherein the burner front is configured to mix the compound with thecombustion air. In this example embodiment, the fuel is natural gasliquid (NGL) and the primary fuel is coal.

In a seventh example embodiment, a utility furnace comprises: a burner;a delivery mechanism, wherein the delivery mechanism is configured todeliver combustion air into the utility furnace, wherein the deliverymechanism is configured to deliver combustion air into the utilityfurnace in the vicinity of the burner, wherein the combustion aircomprises one of primary air, secondary air and tertiary air; a fuelsource provided to the burner, wherein the fuel source is a first fueltype and is the primary source of fuel to the utility furnace; and acompound source, connected to the delivery mechanism, wherein thecompound source is configured to supply the compound into the combustionair in the delivery mechanism. In this example embodiment, the compoundis a second fuel type different from the first fuel type. In thisexample embodiment, the second fuel type is one of: a liquid and a gas.In this example embodiment, the second fuel type is natural gas liquid(NGL). In this example embodiment, the second fuel type is liquefiednatural gas (LNG). In this example embodiment, the first fuel issupplied to the utility furnace in a coal burner tube and wherein thesecond fuel is supplied to the utility furnace through a second tubelocated outside of and proximate to the coal burner tube, wherein boththe coal burner tube and the second tube are located in a windbox of theburner front.

In an example embodiment, any of the preceding example embodiments maybe combined with others of the presented example embodiments set forthabove.

I claim:
 1. A utility furnace comprising: a burner; a deliverymechanism, wherein the delivery mechanism is configured to delivercombustion air into the utility furnace, wherein the delivery mechanismis configured to deliver combustion air into the utility furnace in thevicinity of the burner, wherein the combustion air comprises one ofprimary air, secondary air and tertiary air; a fuel source provided tothe burner, wherein the fuel source is a first fuel type and is theprimary source of fuel to the utility furnace; and a compound source,connected to the delivery mechanism, wherein the compound source isconfigured to supply a compound into the combustion air in the deliverymechanism.
 2. The utility furnace of claim 1, wherein the compound is asecond fuel type different from the first fuel type.
 3. The utilityfurnace of claim 2, wherein the second fuel type is one of: a liquid anda gas.
 4. The utility furnace of claim 2, wherein the second fuel typeis natural gas liquid (NGL).
 5. The utility furnace of claim 2, whereinthe second fuel type is liquefied natural gas (LNG).
 6. The utilityfurnace of claim 2, wherein the first fuel type is supplied to theutility furnace in a coal burner tube and wherein the second fuel typeis supplied to the utility furnace through a second tube located outsideof and proximate to the coal burner tube, wherein both the coal burnertube and the second tube are located in a windbox of the burner front.7. A method of retrofitting a utility furnace, wherein the utilityfurnace has a burner front, wherein the burner front fires the utilityfurnace with a first fuel type, and wherein the burner front suppliescombustion air associated with the combustion of the first fuel type,wherein the combustion air comprises at least one of: primary air,secondary air, and tertiary air, the method comprising: connecting asource of a second fuel type to the burner front, wherein the connectionis configured to introduce the second fuel type into the combustion air;and wherein the first fuel type is a different type of fuel from thesecond fuel type.
 8. The method of claim 7, wherein the utility furnaceis a coal fired furnace and the first fuel type is coal.
 9. The methodof claim 8, wherein the second fuel type is one of: a liquid and a gas.10. The method of claim 9, wherein the second fuel type is natural gasliquid (NGL).
 11. The method of claim 9, wherein the second fuel type isliquefied natural gas (LNG).
 12. The method of claim 8, wherein thesecond fuel type is introduced directly into the combustion air.
 13. Themethod of claim 8, wherein the second fuel type is introduced indirectlyinto the combustion air.
 14. The method of claim 8, wherein thecombustion air is primary air.
 15. A method of injecting a compound intoa utility furnace comprising: delivering a compound into the utilityfurnace by injecting the compound into a delivery mechanism conveying acombustion air, wherein the combustion air is one of primary air,secondary air, and tertiary air, wherein the compound comprises a fuelthat is not a primary fuel for firing the utility furnace.
 16. Themethod of claim 15, wherein the delivery mechanism is a burner front forthe utility furnace, wherein the burner front comprises the burner andwherein the burner front is configured to mix the compound with thecombustion air.
 17. The method of claim 15, wherein the fuel is naturalgas liquid (NGL) and the primary fuel is coal.
 18. The method of claim15, wherein the fuel is liquefied natural gas liquid (LNG) and theprimary fuel is coal.
 19. The method of claim 15, wherein the fuel isone of a liquid and a gas, and wherein the primary fuel is coal.